Well, these are old pages from the 1980s. I'm not sure if this is the story that will be in the Alex Ross Marvels book. However ... seems likely to me.
Well, glad to brighten your day.
I think I also got the idea of Popeye by that note on the bottom of the page that said, "A pointy eared sailor at the bar." LOL!
But we MIGHT be getting exactly this 5 page comic in that Alex Ross Marvel book. It wouldn't be the first time that Marvel has pulled some unpublished piece with Namor out of the drawer. There was that Mark Bagley / Fabian Nic Defenders story that was completely drawn, but not scripted, which Busiek, IIRC, had to basically write the script just based off the art. And wasn't that Al Williamson story in the 70th Anniversary Subby issue one from the vault?
Anyway, seeing this again, it just makes the whole question of Namor's proposed ongoing series even more muddy, since this says Avengers as the title at the top of the page. However, there was a Marvel Age type article that said Shooter was working on a Namor ongoing with Alan Weiss. I'll have to see if I can dig up that article. Maybe this was a trial run for the Namor ongoing? It would be great if we could get clarification from either creator.